From the Glenwood Springs Post Independent (April E. Clark):
[Chad Rudow, water quality coordinator for Roaring Fork Conservancy] said 17 of the 20 sites sampled in the Roaring Fork and Crystal watersheds showed scores indicating healthy conditions. Of the 20 sites, only two, Cattle Creek at the Highway 82 culvert and the Roaring Fork at Slaughterhouse Bridge in Aspen, were considered impaired. Farther upstream in Aspen, the Roaring Fork at the Mill Street Bridge fell into a gray area between healthy and impaired.
The study sampled a variety of aquatic insects, such as mayflies, caddisflies and stoneflies, and used the results to evaluate the health of rivers and streams. The aquatic insects are seen as good indicators of river health because they have limited mobility, high population densities, and spend a relatively long time in their aquatic life stage before hatching out into adults. They are also highly sensitive to disturbance.
“In layman’s terms, these aquatic insects are like the canary in the coal mine of how the rivers are doing,” Rudow said. “They are very intolerant of pollution and are some of the first insects to disappear. They are a good marking point, as they reflect the quality and quantity of the water.”[...]
The study was conducted in late September and early October 2011, a key time of year to study macroinvertebrates, according to Rudow. High snowpack the previous winter led to high streamflows well into the summer of 2011 and likely had a positive effect on the study’s collected data.
Rudow said the study will be repeated during the same period this year, and it may show how much the 2012 drought conditions have impacted streams, rivers and aquatic habitat.
More Roaring Fork River watershed coverage here.